build

en/docs/chapter_heap/build_heap.md

@@ -220,7 +220,9 @@ It's worth mentioning that **since leaf nodes have no children, they naturally f
 
         /* 交换元素 */
         private fun swap(i: Int, j: Int) {
-            maxHeap[i] = maxHeap[j].also { maxHeap[j] = maxHeap[i] }
+            val temp = maxHeap[i]
+            maxHeap[i] = maxHeap[j]
+            maxHeap[j] = temp
         }
 
         /* 获取堆大小 */

en/docs/chapter_heap/heap.md

@@ -649,7 +649,7 @@ We can encapsulate the index mapping formula into functions for convenient later
 
     /* 获取父节点的索引 */
     int parent(MaxHeap *maxHeap, int i) {
-        return (i - 1) / 2;
+        return (i - 1) / 2; // 向下取整
     }
     ```